In an era of bigger is better, Joshua Smith is sculpting hyper-realistic buildings small enough to convince you otherwise.

The Adelaide miniaturist has been recreating iconic city buildings at one-twentieth of the scale for the past three years.

The intricate designs feature cigarette butts and disposed slushie cups, often just millimetres in length, with the hope of bringing attention towards the grime and beauty of urban decay.

"The more decrepit and decayed the building is, the more I want to build it.

"I see the sense of beauty in the decay and the history and the story that it tells, and I want to tell the untold stories, more than the ones that are prominent."

Commissioned by the Australian Design Centre, Mr Smith's latest project depicts three of Sydney's forgotten buildings — the Olympia Milk Bar in Stanmore, the Karim building on Wentworth Street and the Ginseng Shop in Haymarket.

"That's rolled-up paper that I light and very carefully blow out and then put it into the paper."

By focusing on decaying buildings, Mr Smith said he often had to contact the graffiti artists who had already used the space to display their work.

"I get in touch with the graffiti artist personally and get their permission to recreate it exactly, and then I use spray paint to replicate the work."

And while the buildings often look dusty and dirty, Mr Smith said it was not as simple as rubbing the artwork with some dirt from the ground.

"I use weathering pigment," he said.

"If I'm using actual dirt, it can't pass though quarantine when I'm trying to get it into other countries, especially if I'm trying to get it back into Australia just because it's raw, organic materials."

Mr Smith's miniatures are for sale for around $8,000 each.

The Urban Decay Exhibition will run at the Australian Design Centre in Sydney until September 25.